New 2019 Ultimate 2.4 here, and in the last week, the transmission — on the highway at 70 mph — has been refusing to shift into 8th gear, staying in 6th or 7th. If I shift manually up to 8th, it does so without hesitation. As soon as I shift back to full automatic though, the revs climb again, as it shifts back to a lower gear.
I will be calling our dealer for a service appointment, but has anything like this happened to someone else here? If so, what did the dealer do to fix it? Thanks!

 

Since this would be covered by warranty I would suspect an open between the trans control module and the shift solenoid. The solenoid seems to be working, but is not getting the signal to shift from the control section.

 

And, how would this be remedied? Thank you for your advice....the person I made an appointment with said they were going to reflash some of the computers.....is that likely to help?

 

There are some quirks that only a "reflash" can correct. I don't know if this might be one of them. Let' see what happens after they do their thing.

Hope you will share the fix,,,,,,,,,,,if it does the trick, thanks.

 

Wouldn’t you know it, the car has not done this since I posted about it....hopefully there is an error code stored somewhere they’ll be able to see.......

 

Well of course, no error codes stored in the CPU, and no computer updates available from Hyundai..........in and out of the dealer today in 20 minutes.....they did say that this transmission setup is constantly “learning” from your driving style, and if you have driven in town, at slow speeds for several days, that the transmission thinks you no longer “need” 7th or 8th gears until you go back on the freeway for awhile.........don’t know if I swallow that....but regardless, it is shifting quickly and easily into 8th for now, even at city speeds, so I’ll monitor this and see what happens down the road.....

 

Maybe this is one of those times when patience is a virtue, never know !